You are probably meshing with tetrahedral elements, which is why you
have many more elements and nodes and you are running out of memory.
Tets are very inefficient for modeling thin structures.  I recommend
modifying (slicing, merging, etc.) the underlying solid model so that
the structure can be swept mesh with hexs and pyramids.  A swept mesh
will be much more efficient.  Also, I recommending using the current
coupled-field solid element (SOLID226) rather than the older SOLID69
element.

Dan Shaw
ANSYS, Inc



-----Original Message-----
From: mems-talk-bounces@memsnet.org
[mailto:mems-talk-bounces@memsnet.org] On Behalf Of sniper
Sent: Monday, July 13, 2009 10:15 PM
To: mems-talk
Subject: [mems-talk] About Ansys elements, nodes and MEMS meshing

Dear Pros,

 Recently I've been working on a simulation of micro hot plate. The 3D
model was built in Solidworks and then imported into the Ansys.
 I glued all the volumes, and smart meshed them using SOLID69. However,
when I list the elements and nodes number, I found the total number of
elements is approximately 5 times more than that of the nodes. Is the
result supposed to be like that?

 And here is another question: the micro hot plate (a.k.a heating
membrane), is so badly proportioned-like with the width 50um but the
thickness 0.2um and with the substrate 500um thick, when I tried to
model and mesh it in the real size, the Ansys seems to get stucked and
tells me not enough memory. How should I reduce the complexity of the
model without introducing great errors? Could I increase the thickness
of the heating membrane (so that the mesh could be done) and change the
properties of the materials ?

 Thank you very much!

 A rookie in the MEMS field